Cherry-pick missing part of [Clang][Sema] Revert changes to operator=… (llvm#1529)

Author: Salinas, David

clang/lib/Sema/SemaExprMember.cpp

@@ -987,6 +987,8 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
   // arrow operator was used with a dependent non-pointer object expression,
   // build a CXXDependentScopeMemberExpr.
   if (R.wasNotFoundInCurrentInstantiation() ||
+      (IsArrow && !BaseExprType->isPointerType() &&
+       BaseExprType->isDependentType()) ||
       (R.getLookupName().getCXXOverloadedOperator() == OO_Equal &&
        (SS.isSet() ? SS.getScopeRep()->isDependent()
                    : BaseExprType->isDependentType())))